There are usually three types of hydraulic pump constructions within mobile hydraulic applications. These include equipment, piston and vane; however, there are also clutch pumps, dump pumps and pumps for refuse automobiles such as dry valve pumps
The hydraulic pump is the element of the hydraulic system that takes mechanical energy and Hydraulic Pump china converts it into fluid energy in the type of oil flow. This mechanical energy is definitely taken from what’s called the primary mover (a turning pressure) like the power take-off or directly from the truck engine.
With each hydraulic pump, the pump will be of the uni-rotational or bi-rotational design. As its name implies, a uni-rotational pump is designed to operate in one direction of shaft rotation. However, 
a bi-rotational pump has the ability to operate in either path.